Identify families with history of colon ployposis, Gardner's syndrome, or other genetically-related cancers. Obtain the following tissues from the tumor patients and/or families and initiate tissue culture. Characterize cell cultures for the follwoing in vitro properties. Compare fibroblast cell cultures for transformability by Kirsten sarcoma virus (KiMSV), rat sarcoma virus (baboon endogenous virus (BaEV) pseudotype), RD-114 pseudotype and amphotropic murine psuedotype. Attempt to rescue human and primate transforming (src) genes from spontaneous tumors and from human and primate cells transformed by chemicals and/or DNA viruses.